If the code you show is supposed to be what the Curl command does, you have an inconsistency there. You are trying two different files:

~/Desktop/file.pfx
[download]

is very different from

/Downloads/file.pfx
[download]

If the :secret_key in your Curl command means that the file is password protected, you will have to look at how IO::Socket::SSL or Net::SSLeay handle this, depending on which backend your code uses. For IO::Socket::SSL, see the SSL_passwd_cb callback.